Counter circuit



Feb. 2, 1943. P; c. MICHEL 2,310,105

COUNTER CIRCUIT Filed April 16, 1941 2 Sheets-Sheet 1 OUTPUT F iig-ZA.

|23456789l0ll FlcgZB.

OUTPUT i P-DEPENDS ONLY ON c. Rg ANDRm.

isa- '1' 2 I a 4 (5 56:6 6 o--- l oB+ 1-1 Q 9 v' 0 L I SCALE 0F I0 SCALE0F 5 SCALE OF 2 IMPULSE IMPULSE IMPULSE COUNTER COUNTER COUNTER ANDDIVIDER AND DIVIDER AND DIVIDER Inventor: Philip c. Michel,

by I I mttorney Feb. 2, 1943.

P. C. MICHEL COUNTER CIRCUIT Filed April 16, 1941 2 Sheets-Sheet 2 Pi g.4.

Inventor: Philip QMichel,

b )wwy His Atborney.

Patented Feb. 2, 1943 New York Philip G. Mi'clie Schenectady, -.GeneralElectricz' companmi Application April 16, 1941, Serial No. 388,820

9 Claims.

My invention relates to circuits for discharge devices and concernsparticularly counting and timing arrangements.

It is an object of my invention to provide an improved electricalimpulse counter and frequency divider, as well as either a frequencyindicator or timer.

A further object of my invention is to provide such arrangements, whichoperate independently oi the time interval between impulses down to alower limit fixed by the characteristics of discharge devices available,and which is adapted to cascading in stages and to variation of thescale or dividing factor for each stage.

In carrying out my invention in its preferred form I provide a pluralityof electric discharge devices having anodes, cathodes, and controlelectrodes so connected as to form a series circuit when all of thedischarge devices are conducting and having separate cathode resistorsto ground. Suitable couplings between cathodes are provided to preventseries firing of all the tubes when an input signal is applied to thecontrol electrodes, whereby one tube is ignited at a time, the firstdischarge device and its anode circuits being supplied by a source ofanode voltage and each succeeding discharge device having the anodesupplied by the voltage across the cathode resistor of the precedingdischarge device. In this way the first impulse fires or ignites thefirst tube and raises the voltage across its cathode resistorsufiiciently to ignite the second tube when the next impulse isreceived. Successive impulses ignite additional tubes so that the numberof impulses whichhave been received is indicated by determining thenumber of discharge devices which are conducting. A connection isprovided between the last discharge device and the first to extinguishthe discharge in all of the devices when the last discharge devicebecomes conducting. A connection taken from the circuit of the lastdischarge device may be utilized to supply impulses to a second stage inwhich the number of impulses received is a fraction of the impulsessupplied to the preceding stage. The dividing factor of each stage isdetermined by the number of discharge devices in the stage.

A better understanding of the invention will be afi'orded by thefollowing detailed description considered in connection with theaccompanying drawings, in which Fig. 1 is a circuit diagram of a countercircuit having a scale of 5 which may be employed as one stage of'amultistage counter system; Figs. 2A and 2B are graphs representing theinput and output voltages of the circuit represented in Fig. 1; Fig. 3is a schematic diagram representing a cascading arrangement; Fig. 4 is acircuit diagram illustrating a modification of Fig. 1 using a vacuumtype extinguishing tube; and Fig. 5 is a modification of Fig. 4 for ascale of 2. Those features of my invention which are believed to benovel and patentable are pointed out in the claims appended hereto.

In Fig. 1 there is illustrated a counter circuit which may be utilizedindependently as a counter for counting the remainder of any number ofimpulses divided by 5, and as a frequency divider for producing impulsesone-fifth as great in number as the input impulses, or which may serveif desired as an intermediate stage I 0 of a multistage systemrepresented diagrammatically in Fig. 3. There is provided an inputterminal Ii with a neutral terminal H, which may be grounded, so that aninput voltage signal may be applied between the terminals II and i2.There is an output terminal l3 and the output signal appears as avoltage between the terminals l2 and It. A plurality of dischargedevices T1, T2. T3, T4, and T5 is provided having electrodes designatedby letter symbols with appropriate subscripts corresponding to those ofas vapor electric discharge tubes, ionic discharge tubes, andThyratrons. However, I shall employ the term "gaseous discharge tube and"gaseous discharge device throughout the description and claims to referto discharge devices of the type having the characteristics mentioned,regardless of their actual construction.

A source of anode voltage is provided and may be connected between theterminal 3+ and the ground terminal l2. A plurality ofcurrent-conducting cathode impedances such as resistors R1a, Rn, Rm,R19, and R15 is connected in the'cathodeto-ground circuits of thedischarge tubes T1, T2,

- T3, T4, and T5 respectively. The tubes also have connections from thecathode of one to the anode of the next. so that they may be consideredas connected in series between the anode source 3+ and the groundterminal l2. Bubstantially non-conductive coupling devices such ascondensers Ci, Ca, Ca, 04, and Cs are connected between the input signalterminal ii and the control electrodes 001 to CG; of the tubes T1 to T5.

The source of negative biasing voltage is connected between the biasterminal C- and the ground terminal II. For connecting the negative biasterminal to the control electrodes a plurality of relativelylow-conductance connections such as resistors R1-Rs of the order. of amegohm is provided. In order to prevent the eifective bias potential ofthe control electrodes from falling too far below the cathode potentialsand injuring the discharge tubes, voltage divider circuits arepreferably provided formed by connecting resistors Rs-Rm between thecontrol electrodes and cathodes of the tubes Tl-Td respectively, theresistors RsR1o having smaller resistances thanthe resistors R1Rs andthe voltage dividers being formed by the series connections of theresistors. In the case of TI. the voltage divided consists of theresistors Bi and Rs in series.

The arrangement is such that a discharge as initiated in tube Ti, whichmay be referred to as the initiating tube and the discharge isextinguished by the action of the tube To, which may be referred to asthe extinguishing tube. The remaining devices Ta, '1: and T4 may beincreased or reduced in number or may be omitted entirely according tothe division factor desired between input and output signals, and thesetubes if employed are referred to as intermediate tubes. Couplingcondensers Ca. Ca, and Cs are provided between the cathodes of theintermediate tubes T2, T3, and T4 and the cathodes of the precedingtubes. Resistors R11, R1: and R1: are included in the respectiveconnections. The extinguishing tube T5 has its anode A5 connected to thecathode K4 of the tube T4 by means of a resistor R14 and a condenser Cois connected between the anode A5 and ground. The time constant of thecircuit R14, C9 is made large enough so that, when the tube T4 ignites.the rise of the anode potential of the extinguishing tube Ts to theignition level will be delayed until the control electrode CGs hasdropped sumciently negative to hold of! conduction of the tube To.

The condensers Cs, C1 and Ca in the connections between the cathodes ofthe intermediate tubes and the preceding tubes have sufllcient capacityto raise the cathode potential of a tube with its anode potential whenthe preceding tube fires in order to prevent firing of both tubes. Forexample, the capacity of the condenser Cs is sufllciently large and theresistance of the resistor R11 is suiliciently small in relation to theresistance of the resistor Rn, so that the potential of the cathode K:rises when the potential of anode A1 is raised by the passage of currentthrough the cathode resistor Ru: and the potential of the cathode K:remains high until the input signal disappears, whereby the potentialdifierencebetween the electrodes A: and K: remains less than required tomaintain an arc until the control electrode CG: is no longer at positivepotential. The resistors R11, R1: and R1: in the connections between thecathodeshave such resistances as to. limit the anode currents in theintermediate discharge devices during discharge thereof and to permitgradual dissipation of the energy stored in each of the condensers Cs.C1 and Cs when the corresponding discharge tube ignites. For example,after a suflicient time delay the condenser Cs becomes charged, thepotential existing across the cathode resistor Rm. Then when the tube I:is ignited by the second input impulse, the resistor Ru limits to a,safe value the current discharging the condenser Cs through the tube T2.

For extinguishing the discharge in the initiating tube Tl when theextinguishing tube To is ignited, a relatively large condenser C10 isconnected between the cathode of the extinguishing tube To and thecathode of the initiating tube T1. The time constant of the circuit C10,R15 is made small enough so that the charging of the condenser Cm(initiated by the firing of the tube Tl) will not hold the cathode ofthe extinguishing tube To positive ior such a long time as to preventfiring .on.each fifth impulse at the highest input pulse frequency to beused. The time constant of the circuit of the condenser C9 dischargingthrough To into R15 and through the condenser Cm into'theresistor R16effectively shunted by R17, Rn, Rio, and Rn is made large enough,however; to hold the oathode Kl of the initiating tube Tl positive untilthe initiating tube T1 is deionized, and its control grid has fallenfromthe fifth impulse to a potential which prevents recurrence ofconduction on that impulse.

The-anode As Of the extinguishing tube T5 may be employed as the outputterminal if the circuit into which the output feeds is not such astoreact objectionably upon the counter circuit and if an output impulse ofreversed polarity is acceptable. However, I consider it advantageous toprovide an isolating and coupling circuit which reverses the polarityfrom that of the anode A5 to provide amplified output impulses of thesame polarity as the input. The coupling circuit for the output may takethe form of a discharge device Ts with an anode As, a control electrodeor grid Go and a cathode Ks. A coupling condenser Cu may be connectedbetween the anode A5 and the control grid Gs with a resistor R20interposed, and a gridleak resistor R21 may be connected between thecontrol electrode and the cathode. If the coupling circuit is,.to servealso as a polarity reversing circuit, an anode resistor R2: isadvantageously connected between the voltage source terminal 3+ and theanode As and the tube Ts is advantageously of the continuous control orvacuum type, sometimes called a hard tube. For restoring all of thetubes to the non-conducting condition a reset switch It may be connectedbetween the anode voltage source 3+ and the anode A1 of the initiatingtube T1.

For conveniently indicating which of the tubes is the last to becomeconducting, voltage responsive indicators, preferably of the zero or lowcurrent drain type such as neon discharge tubes, are connected betweenthe anodes and cathodes of the tubes T1Ts, and they carry the scalenumerals 0,1, 2, 3, and 4, respectively, to indicate the number ofimpulses received in a manner which will be explained hereinafter.

It will be understood that if discharge devices of the indirectly heatedcathode type are employed, a suitable source of heater current. notshown, is provided, and this source may be held and flowing at apositive potential by means oi a tap on a voltage divider, not shown,connected across the anode voltage source to prevent excessive potentialdiflerence between the heaters and the cathodes.

The manner in which the indicators 0, 1, 2, 3, and 4 indicate the numberof impulses which have been received will be apparent from aconsideration of the manner of operation of the circuit. Before anyimpulses have been received and when none of the tubes are conducting,the full voltage of the Hide source 3+ t ground appears across the anodeand cathode of the initiating tube T1. Consequently, voltage alsoappears across the zero-indicating device 0, The fact that this deviceis energized or lighted indicates that the count thus far is zero. Theother indicators i, 2, 3, and l are dark for the reason that theseremaining tubes obtain their voltage from the potential drop across thefirst cathode resistor Rm which at this'time carries no current andtherefore has a zero potential drop. When the first impulse is appliedto the input terminal ll the control electrodes of all five dischargetubes are driven positive to overcome the negative bias of the sourceC-. Accordingly, the initiating tube T1 becomes conducting. The othertubes do not become conducting, however, because they have no anodevoltage applied. As current begins to flow in the cathode resistor R16it raises the potential of the anode A2 of the first intermediate tubeT2 but the capacitative coupling Ce causes the potential of the cathodeK2 to rise with that of the anode A2, thus preventing ignition of thefirst intermediate tube T2. Since the input impulses are of short timeduration, the positive voltage impulse applied to the. control electrodeCG: will have disappeared before the potential of the cathode K: hasfallen sufficiently below that of the anode A2 for ignition of T2. Therate at which the potential of the cathode K: falls to zero isdetermined by the time required for the condenser Co to charge throughthe resistors R11 and R17. Potential appearing between A2 and K: causesthe indicator i to light, and at the same time the reduction ofpotential between A1 and K1, due to conduction of T1, extinguishes theindicator 0.

When the next input signal is received the control electrodes are againdriven positive and this time the first intermediate tube T1 ignitesbecause its anode is energized by the voltage across the resistor Rm.The ,condenser Ca thereupon discharges through the tube T2 but thedischarging current is limited by the resistor R11 to pro-= tect thetube. Since the tubes T1 and T2 are now both conducting the indicatingdevices and i are both shunted so that they do not l ghtup. Voltage.appears, however, across the indicating device 2 connected. across thetube Ta sincethere is now a voltage drop across the cathode resistorR11. Ignition at this time of the tube T3 was prevented by the couplingC1 in the same manner as previously discussed.

Subsequent impulses will ignite the additional tubes one at a time. Eachtime the number of.

impulsesreceived will be indicated by which one of the indicatingdevices 04 is energized, all but one of these being deenergized for thereasons explained. When the fourth impulse is received the voltageacross the cathode resistor R1 rises as in the previous case. However,the extinguishing tube T5 is prevented from firing by reason of the timedelay required for the condenser Cu to be charged suiiiciently to raisethe anode potential extinguishing tube Ts becomes conducting and thepotential rises across the cathode resistor R15. The relatively highcapacity connection between the cathode K5 and the cathode K1momentarily raises the'potential of the cathode K1 above that of theanode T1 so as to extinguish the discharge in the initiating tube T1.Before the condensers Co and 010 have discharged to lower the cathodepotential of the initiating tube T1, that tube has become deionized sothat current therein ceases and the voltage drop across the resistor R16falls to zero. The ignition of the remaining tubes Tar-T5 has therebyalso been extinguished. The circuit is thus restored to its initialcondition and the same action may be repeated indefinitely. After anynumber of impulses the indication last produced will beretained if nofurther impulses are received, because the circuit is stable and doesnot depend upon the retention of charge by a condenser.

It will be understood that my invention is not limited to the use ofcircuit elements having speciflc numerical values of constants nor tothe use of particular classes of electric discharge devices. I havefound, however, that satisfactory results may be obtained by employinggas tetrodes of the construction designated as 2051 for the gaseousdischarge devices T1 to T5, by employing a vacuum type triode consistingof half a-tube known by the designation 6N7 to form the couplingdischarge device Te and by using numerical values of circuit constantsindicated in the following tabulation:

C1-C5 micromicrofarads 40 Cc-Cs microfarad .006 C9 do .02 Clo .05 C11micromicrofarads 20 R1-R5 megohms 2 Rc-=Rio 0.5 R1iR1: ms 1,000 R14 do10,000 Rue-R19 fin 50,000 R20 megohms 0.5 R21. o 0.15 Rn ohms 15,000 3+volts 300 C do The indicators 0 to 0 may be neon tattelites withone-half megohm series resistors.

Utilizing the tube classifications as specified,

* when using input voltage signals of 20 volts or more, the input sine]wave may be represented by the graph of Fig. 2A where the duration ofthe positive signal impulses may be microseconds or less. The intervalbetween input impulses may be any value greater than 500 microseconds.The limiting'yalues depend of course upon the tube characteristics.Employing five tubes in order to obtain a scale of five as shown in Fig.l. the output voltage signal is represented by Fig. 23, where thevoltage is approximately volts with the circuit constants specified. Theduration of the output signal impulse depends only upon the magnitudesof the elements in the coupling circuit. viz: the condenser Cu andresistors R20 and R21.

As already mentioned. the number of intermediate, tubes T2 and T4 may bechanged. or they may be eliminated entirely in order to change thedivision factor between the number of input and output signals. Forexample, if the intermediate tube Ta is removed together with all of theapparatus within the dotted rectangle IS, the number of output impulseswill be one-fourth the number of input impulses. If all three tubes T2,T3 and T4 are omitted, together with the other elements corresponding tothose within the dotted rectangle IS, the scaleof-two counter is formedhaving an initiating tube T1. and the extinguishing tube T5. 11' adecimal'system of counting is desired, five additional tubes may beadded to the circuit of Fig. 1 to form a. scale-of-IO counter anddivider. Alternatively, the circuit shown may be cascaded with ascale-of-two impulse counter or divider to produce a division by 10. Anynumber of such circuits may be cascaded as desired or the impulsecounter Ill may be cascaded with impulse counters and dividers of otherelectrical or mechanical types according to the anticipated frequency ineach stage of the counting system, each'stage eflecting a divisionaccording'to its scale.

I have referred to my circuit particularly in connection with its use asa counter of impulses or as a divider of the frequency or the number ofimpulses. However, the circuit may be employed as a timer if the inputsignals are supplied from a constant frequency source, or the circuitmay be used as a frequency me'ter if the impulses are supplied for afixedtime duration.

In the arrangement illustrated in Fig. 1, premature ignition of theintermediate tubes is prevented by condensers Ca, 01, and Ca which areeach connected between the cathode of an intermediate tube and thecathode of the preceding' tube. Premature ignition of the extinguishingtube Ts when the preceding tube ignites is prevented, however. by acondenser between the anode of the extinguishing tube and the groundconnection l2 with the resistor R14 interposed in the anode lead of thenextinguishing tube Ts.

My invention is not limited, however, to having only the extinguishingtube connected in this manner for prevention of premature ignition. Thearrangement illustrated has the advantage, nevertheless, that there isless condenser energy to'be dissipated when the extinguishing tube Tsbecomes conducting for the reason that the condensers Co, Cr, and Cs aredischarged before the tube Ts becomes conducting.

Although I have illustrated and described a counter or divider circuitin which the last stage tube, that is, the extinguishing tube T5 is ofthe gaseous type, it is to be understood that my invention is notlimited to the precise arrangement thus far described. Since theextinguishing tube '1; is not required to remain conducting after thevoltage impulse which fires it disappears. it is not necessary that theextinguishing tube be of the gaseous or ionic discharge type. A socalledhard tube or vacuum tube may also be employed.

If desired, the extinguishing tube may take the form of a four-elementvacuum discharge device having a second grid or positive electrodereferred to as a screen grid, as illustrated in Fig. 4. In Fig. 4 thegaseous discharge device Ts is replaced by a vacuum tube l'l having ananode it directly connected to the anode voltage source 13+ and havingthree other electrodes connected as a triode in the same manner as theanode, control electrode and cathode of the gaseous discharge tube shownin Fig. 1. The

vacuum tube "may be of the type designated as 6L6 for example. Thevacuum tube II has a screen grid is which may be considered either as asecond control electrode or a second positive electrode, correspondingto the anode of a triode and the positive electrode [9 is connectedthrough the resistor R14 to the cathode of the preceding tube as inFig. 1. The vacuum tube I! has also acontrol electrode CGs and a cathodeKs corresponding to the electrodes bearing the same reference numeralsin Fig. 1. It will be understood that the negative bias applied to thecontrol electrode CG: of the'tube I'I should be so chosen as to give thebest results with this type of tube and the relative magnitudes of thepotentiometer resistors R5 and Rm are so chosen as to give the desirednegative bias. To simplify the drawing, some of the intermediate stagesscale-of-three counter.

have been omitted in Fig. 4 and are indicated simply by the dottedrectangle 20. If these are omitted, the arrangement of Fig.4 becomes aIn considering the electrodes is, CGs and Ks as a triode, the operationof the circuit of Fig.

4 is the same as that of Fig. 1. When the first positive voltage impulseis applied to the input electrode II, the initiating tube T1, a gaseoustube is fired. This operation short-circuits the neon tube I, causingthe light to go out and the voltage drop across the cathode resistor Ruapplies voltage to the anode A2 of the intermediate tube T: and alsoapplies voltage to the neon tube I. The neon tube l is thus illuminatedto indicate that the first impulse has been received. On the applicationof a second voltage impulse to the input terminal II, the intermediatetube T: fires and voltage'appears across the resistor Rn. Assuming theadditional stages 2| have been omitted, the voltage is then appliedthrough the resistor, R14 to the screen grid I! of the vacuum tube l1and to the neon tube which-is connected between the screen grid and thecathode of the vacuum tube IT. The vacuum tube It is prevented fromfiring, however. by reason of the time delay produced by the connectionof the condenser Ca between the screen grid l9 and the terminal II. Thisholds the screen grid I! at a sufiiciently low potential momentarily toprevent a discharge in the tube ll until the impulse applied to theterminal II has fallen to zero. Gradually the potential of the screengrid it rises to the value of the voltage drop across the cathoderesistor of the preceding tube and thus the vacuum tube I! is primed foroperation upon reception of the next impulse applied to the inputterminal I I. when the next impulse is received it raises the potentialof the control electrode CG; and causes the tube I I to fire. The

screen grid l9 carries relatively little current and serves to dischargethe time delay condenser C5. However, the anode l8 suppliesthe principalportion of the discharge current which flows through the cathoderesistor R15, causing a sudden rise in the potential of the cathode K5.This potential is transmitted to the cathode K1 of the initiating tubethrough the condenser C10, and the initiating tube T1 is extinguished inthe samemanner as explained in connection with Fig. 1.

The circuit. of Fig. 4 may be converted to a scale-of-two-counter in thesame manner as the circuit of Fig. 1 by omitting also the intermediatetube T: with its associated circuit elements CI,'R11, R11, neon tube I,coupling condenser C2. potentiometer resistors R1 and R2. The resistorR14 will then be connected directly between the triode portion of thetube I'I, that is, to the screen grid l9.

However, the use of a hard tube for the screen grid for theextinguishing function permits a further simplification in the case of ascale-oftwo-counter. As illustrated in Fig. the time delay elements R14and C may be omitted in the simplified arrangement illustrated in Fig.5. Since the screen grid I9 is not required to supply appreciablecurrent for the discharge of the tube il, a condenser such as thecondenser Co is not required between the screen grid I9 and the groundconnection for supplying energy to produce a strong discharge in'thevacuum tube II. The energy in this case comes from the anode voltagesource B+ which is connected to the anode l8. There is also no need forthe elements R14 and Co to introduce time delay in the applicationvoltage to the screen grid I9 when the tube T1 fires because thecondenser C connected between the cathodes of the two tubes causes thepotential of the cathode K5 of the tube i! to rise momentarily when theinitiating tube T1 fires, thus preventing sufilcient potentialdiiference between the screen grid I9 and the cathode K5 to permitpremature ignition of the tube ii.

In accordance with the provisions of the patent statutes, I havedescribed the principle of operation of my invention, together with theapparatus which I now consider to represent the best embodiment thereof,but I desire to have it understood that the apparatus shown is onlyillustrative and that the invention may be carried out by other means.

What Iclaim as new and desire to secure by Letters Patent of the UnitedStates is:

1. A counter circuit comprising a. plurality of gaseous dischargedevices including an initiating discharge device, an extinguishingdischarge device, and one or more intermediate discharge devices, eachdischarge device having an anode, a cathode and a control electrode, aninput terminal adapted to have electrical impulses to be counted appliedthereto, a ground terminal, an output terminal, an anode voltage sourceterminal, a negative bias voltage source terminal, a plurality oflow-current-drain indicators equal in number to the said gaseousdischarge devices each connected between the anode and the cathode ofone of said discharge devices, a plurality of cathode resistors eachconnected between one of said cathodesand said ground terminal,substantially non-conductive couplings between said input terminal andsaid control electrodes, low conducttance connections between said biasvoltage terminal and said control electrodes, 2. connection between saidanode voltage terminal and the anode of said initiating dischargedevice, a plurality of connections each between the cathode ofonedischarge device and the anode of the next whereby all of thedischarge devices are connected in series, the initiating dischargedevice being the first and the extinguishing discharge device being thelast in the series, a resistor being included in the connection betweenthe anode of the extinguishing discharge device and the'cathode of thepreceding discharge device, a plurality of connections each includingresistance and capacitance in series between the cathode of eachintermediate discharge device and the cathode of the preceding dischargedevice in the series, a relatively large condenser connected between thecathodes of the initiating and extinguishing dis charge devices and avoltage-reversing coupling circuit having .an input side connectedbetween the anode of the extinguishing discharge device and the groundterminal and having an output side connected between the said outputterminal and ground, whereby the anode-cathode circuit of the initiatingdischarge device is energized from said anode voltage supply terminaland each of the other discharge devices is energized by the voltageacross the cathode resistor of the preceding discharge device in theseries, and each electrical impulse applied to the input terminal firesthe first discharge device in the series which is not already conductinguntil the extinguishing discharge device is caused to become conductingwhereupon all of the discharge devices are extinguished, each of saidindicating devices thus being energized only when the discharge device 1across which it is connected has voltage applied to the anode butis notconducting so that the number of impulses is indicated by which one ofthe indicating devices is energized.

2. A counter circuit comprising a plurality of gaseous dischargedevices, each discharge device having an anode, a cathode and a controlelecbias voltage terminal and said control electrodes,

a connection between said anode voltage terminal and the anode of thefirst of said discharge devices, connecting means between the cathode ofany discharge device and the anode of the next whereby the dischargedevices are connected in series, a resistor being included in theconnecting means between the anode of the last discharge device and thecathode of the preceding discharge device, a. condenser connectedbetween the anode of said last discharge device and said groundterminal, substantially non-conductive coupling means between thecathode of each discharge device and the cathode of the discharge devicefollowing it including such coupling means between the last dischargedevice and the first, but excluding such coupling means between the lastdischarge device and the one preceding it other than the first, wherebythe anode-cathode circuit of the first discharge device is energizedfrom said anode voltage supply terminal and any other discharge deviceis energized by the voltage across the cathode resistor of the precedingdischarge device in the series and each electrical impulse applied tothe input terminal fires the first discharge device in the series whichis not already conducting until the last discharge device is caused tobecome conducting whereupon the entire series of discharge devices isextinguished.

3. A counter circuit comprising a plurality of gaseous discharge devicesincluding an initiating discharge device, an extinguishing dischargedevice and one or more intermediate discharge devices, each dischargedevice having an anode, a cathode and a control electrode, an inputterminal adapted to have electrical impulses to be counted appliedthereto, a ground terminal, an anode voltage source terminal, means forbiasing the control electrodes of said discharge devices tonon-conductive condition, a plurality of voltage responsive indicatorseach connected between the anode and the cathode of one of the dischargedevices, a plurality oi cathode resistors each connected between one ofsaid cathodes and said ground terminal, substantially nonconductivecouplings between said input terminal and said control electrodes, aconnection between said anode voltage terminal and'said initiatingdischarge device, a plurality of connections each between the cathode ofone discharge device and the anode of the next whereby all of thedischarge devices are connected in series, the initiating dischargedevice being the first and the extinguishing discharge device being thelast in the series, means interposed between the circuit 01' eachdischarge device and the following one to maintain the potentialdiflerence between the anode and cathode of the following dischargedevice substantially unchanged momentarily, means interposed between thecircuit of the extinguishing discharge device and the initiatingdischarge deviceto cause a change in potential in the same direction totake place momentarily in the cathodes or both said discharge deviceswhen the extinguishing discharge device becomes conducting, whereby theanodecathode circuit of the initiating discharge device is energizedfrom said voltage supply terminal and each of the other dischargedevices is energized by the voltage across the cathode resistor 01' thepreceding discharge device in the series, and each electrical impulseapplied to the input terminal fires the first discharge device in theseries which is not already conducting until the extinguishing dischargedevice is caused to become conducting whereupon all of the dischargedevices are extinguished, each of said indicating devices thus beingenergized only when the discharge device across which it is connectedhas voltage appliedto the anode but is not conducting so that the numberof impulses is indicated by which one 01' the indicating devices isenergized.

4. A counter circuit comprising a pair of gaseous discharge devicesreferred to as an initiating discharge device and an extinguishingdischarge device, each discharge device having an anode, a cathode and acontrol electrode, an input terminal adapted to have electrical impulsesto be counted applied thereto, a ground terminal, an output terminaloperatively connected to the anode of the extinguishing dischargdevice,'an

- anode voltage source terminal, a negative bias voltage sourceterminal, a pair or cathode resistors each connected between one of saidcathodes and said ground terminal, substantially nonconducting couplingsbetween said input terminaland said control electrodes. low conductanceconnections between said bias voltage terminal and said controlelectrodes, a connection between said anode voltage terminal and theanode of said initiating discharge device. a re- I sistor connectedbetween the cathode of the initiating discharge device and the anode ofthe extinguishing discharge device whereby the discharge devices areconnected in series, a relatively large condenser between the cathodesoi the initiating and extinguishing discharge devices and a time delaycondenser connected between the anode of the extinguishing dischargedevice and the ground terminal, whereby the anode cathode circuit of theinitiating discharge device is energized from said anode voltage supplyterminal and the extinguishing discharge device is energized by thevoltage across the cathode resistor or the initiating discharge deviceand sucthe ignition oi the extinguishing discharge device simultaneouslyraising the cathode potential 01' the initiating discharge device by thecapacitive coupling between cathodes to extinguish the discharge in bothdevices.

5. A counter or divider comprising a plurality of gaseous dischargedevices and having an anode, a cathode and a control electrode, an inputterminal adapted to have electrical impulses to be counted appliedthereto, a ground terminal. an anode voltage source potential, means forholding the control electrode potential sufiiciently low for normallypreventing ignition of the discharge devices, a plurality of currentconducting cathode impedances each connected between one of saidcathodes and said ground terminal, coupling elements for maintaining thepotential diflerence between anode and cathode of any discharge devicesubstantially unchanged momentarily during ignition oi the precedingdischarge device, a connection between said anode voltage terminal andthe anode oi the first or said discharge devices, connecting meansbetween the cathodeof any discharge device and the anode of the next forconnecting the discharge devices in series, and means for momentarilyfixing the potential diflerence between the cathodes oi. the first andlast discharge devices during ignition or the last discharge device,whereby the anode-cathode circuit of the first discharge device isenergized from the anode voltage supply terminal and any other dischargedevice is energized by the voltage across the cathode impedance of thepreceding discharge device in the series and each electrical impulsefires the first discharge device in the series which is not alreadyconducting until the last discharge device is caused to becomeconducting and to raise the cathode potential of the first dischargedevice for extinguishing all of the discharge devices.

6:A counter or divider circuit comprising a sly low for normallypreventing current conduction by the discharge devices, a plurality ofcurrent-conducting cathode impedances each connected between one of saidcathodes and said ground terminal, coupling elements for maintaining thepotential difierence between the positive electrode and the cathode ofany discharge device substantially unchanged momentarily during ignitionof the preceding discharge device, a connection between said positiveelectrode voltage source terminal and the positive electrode 01 thefirst of said discharge devices, connecting means between the cathode ofany discharge device and the positive electrode of the next i'orconnecting the discharge devices in series, with the said extinguishingdischarge devices being the last in the series, and means formomentarily fixing the potential difierence between the cathode oi theextinguishing discharge device and the first discharge device in theseries during ignition of the extinguishing discharge device whereby thepositive electrode to cathode circuit of the first discharge device isenergized from the positive electrode voltage supply terminal and anyother discharge device has voltage supplied by the potential differencein the cathode impedance of the preceding discharge device in theseries, and each input impulse fires the first discharge device in theseries which is not already conducting until the extinguishing dischargedevice is caused to become conducting to raise the cathode potential ofthe first discharge device for extinguishing all of the dischargedevices.

'7. A circuit comprising an initiating discharge device of the gaseousdischarge type and an extinguishing discharge device, each'dischargedevice having a positive electrode, a cathode and a control electrode,an input terminal adapted to have electrical impulses to be countedapplied thereto, a ground terminal, a positive electrode voltage sourceterminal, means for holding the control electrode potentialssufiiciently low for normally preventing current conduction by thedischarge devices, couplings between said input terminal and saidcontrol electrodes, a, connection between said positive electrodevoltage source terminal and the positive electrode of the saidinitiating discharge device, a connection between the cathode of theinitiating discharge device and the anode of the extinguishing dischargedevice whereby the discharge devices'are connected in series, a pair ofcathode impedances each connected between one of said cathodes and saidground terminal, and a relatively large condenser connected between thecathodes, whereby the positive electrode to cathode circuit of theinitiating discharge device is energized from said positive electrodevoltage source terminal and the extinguishing discharge device hasvoltage applied between the positive electrode and-cathode by thepotential difference across the cathode im- A pedance of the initiatingdischarge. device, and successive electrical impulses applied to theinput terminal first fire the initiating discharge de- 'vice and thenthe extinguishing discharge device with the ignition of theextinguishing discharge device simultaneously raising the cathodepotential of the initiating discharge device by the capacitive couplingbetween cathode to extinguish the discharge in both devices.

8. A circuit comprising a plurality of discharge devices including aninitiating discharge device and an extinguishing discharge device, theextinguishing discharge device being of the vacuum type having an anode,an auxiliary positive electrode, a control electrode and a cathode,except for the extinguishing discharge device said discharge devicesbeing of the gaseous discharge type each having a positive electrode, acontrol electrode and a cathode, an input terminal adapted to haveelectrical impulses to be counted applied thereto, a ground terminal, apositive electrode voltage source terminal, substantially non-conductingcouplings between said input terminal and said control electrodes, meansfor holding the control electrode potentials sufiiciently low fornormally preventing appreciable current conduction by the dischargedevices, a plurality of current conducting cathode impedances eachconnected between one of said cathodes and said ground terminal,coupling elements for maintaining the potential diiference between thepositive electrode and cathode of any discharge device substantiallyunchanged momentarily during ignition of the preceding discharge device,a connection between said positive electrode voltage source terminal andthe positive electrode of the initiating discharge device, connectingmeans between the cathode of any discharge device and the positiveelectrode or the next for connecting the discharge devices in serieswith the initiating device first in the series and the extinguishingdischarge device last, the

extinguishing discharge device being considered as a triode in saidseries circuit with the auxiliary positive electrode serving as thepositive electrode of the triode, and means for momentarily fixing thepotential difference between the cathodes of the first and lastdischarge devices, and a connection between the positive electrodevoltage source terminal and the anode of the extinguishing dischargedevice, whereby the positive electrode to cathode circuit of the firstdischarge device is energized from the positive electrode voltage sourceterminaland any other discharge device except the extinguishingdischarge device is energized by the voltage across the cathodeimpedance of the preceding discharge device in the series, theextinguishing discharge has ltsanode energized by said positiveelectrodevoltage source terminal and its auxiliary positiv electrodeenergized by the voltage across the cathode impedance of the precedingdischarge device in the series, and each electrical impulse fires thefirst discharge device in the series which is not already conductinguntil the extinguishing discharge device is caused to become conductingand to raise the cathode potential of a first discharge forextinguishing all of the discharge devices.

' counted applied thereto, a ground terminal, an

the auxiliary positive electrode of the extinguish-- ing dischargedevice, and a condenser connected between the cathodes of the dischargedevices, whereby the anode-cathode circuits of the discharge devices aresupplied by said anode voltage source and the auxiliary positiveelectrode to cathode circuit of the extinguishing device is supplied by'the potential difierence in the oathode impedance of the initiatingdischarge device when the initiating discharge device is conducting, andwhereby successive electrical impulses applied to said input terminalfire the initiating discharge device and then the extinguishingdischarge device with the ignition of, the extinguishing dischargedevice simultaneously raising the cathode potential of the initiatingdischarge device by the capacitive coupling between the oathodes toextinguish the discharge in both devices.

PHILIP c. mom.

